Detection of Chemical Exchange Saturation Transfer (CEST) Contrast Using Frequency Transfer

Joshua Friedman^1,2, Michael McMahon¹, James Stivers², Peter Christiaan van Zijl¹

Currently, CEST compounds are detected using radiofrequency (RF) based saturation transfer followed by asymmetry analysis of the magnetization transfer spectrum. We report an approach that, instead of saturation transfer, employs a series of so-called label-transfer modules (LTMs), in which frequency labeling and consecutive transfer of labeled protons to water is achieved. No asymmetry analysis is needed and exchangeable protons at multiple frequencies can be detected simultaneously through the water proton signal, while maintaining specific frequency information of the individual solute protons. As a first example, the method is applied to a DNA sample and the theory confirmed experimentally.